Experimental (UV, NMR, IR and Raman) and theoretical spectroscopic properties of 2-chloro-6-methylaniline (original) (raw)
Related papers
Journal of Molecular Structure
In this work, the experimental and theoretical vibrational spectra of 2-chloro-5-methylaniline (2Cl5MA, C 7 H 8 NCl) were studied. FT-IR and FT-Raman spectra of 2Cl5MA in the liquid phase were recorded in the region 4000-400 cm À1 and 3500-50 cm À1 , respectively. The structural and spectroscopic data of the molecule in the ground state were calculated by using Hartree-Fock and density functional method (B3LYP) with the 6-31G(d), 6-31G(d,p), 6-31+G(d,p), 6-31++G(d,p), 6-311G(d), 6-311G(d,p), 6-311+G(d,p) and 6-311++G(d,p) basis sets. The vibrational frequencies were calculated and scaled values were compared with experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies are found to be in good agreement. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The optimized geometric parameters (bond lengths and bond angles) were compared with experimental values of aniline and p-methyl aniline molecules.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2009
In this work, the experimental and theoretical vibrational spectra of 2-chloro-4-methylaniline (2Cl4MA, C 7 H 8 NCl) were studied. FT-IR and FT-Raman spectra of 2Cl4MA in the liquid phase have been recorded in the region 4000-400 cm −1 and 3500-50 cm −1 , respectively. The structural and spectroscopic data of the molecule in the ground state have been calculated by using Hartree-Fock (HF) and density functional method (B3LYP) with the 6-31G(d), 6-31G(d,p), 6-31+G(d,p), 6-31++G(d,p) and 6-311G(d), 6-311G(d,p), 6-311+G(d,p), 6-311++G(d,p) basis sets. The vibrational frequencies have been calculated and scaled values have been compared with experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies are found to be in good agreement. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The DFT-B3LYP/6-311++G(d,p) calculations have been found more reliable than the ab initio HF/6-311++G(d,p) calculations for the vibrational study of 2Cl4MA. The optimized geometric parameters (bond lengths and bond angles) were compared with experimental values of aniline and p-methylaniline molecules.
FT-IR, FT-Raman, NMR spectra and DFT calculations on 4-chloro-N-methylaniline
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2010
In this work, the vibrational spectral analysis was carried out by using FT-IR and FT-Raman spectroscopy in the range 400–4000 and 50–3500 cm−1 respectively, for the title molecule. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method using 6-311++G(d,p) basis set. The vibrational frequencies were calculated and scaled values were compared with experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies are found to be in good agreement. The complete assignments of all the vibrational mode were performed on the basis of the total energy distributions (TED). 13C and 1H NMR chemical shifts results were given and are in agreement with the corresponding experimental values. The theoretically constructed FT-IR and FT-Raman spectra exactly coincides with experimental one.
Journal of Physical Organic Chemistry
In this work, the experimental and theoretical vibrational spectra of N1-methyl-2-chloroaniline (C 7 H 8 NCl) were studied. FT-IR and FT-Raman spectra of the title molecule in the liquid phase were recorded in the region 4000-400 cm S1 and 3500-50 cm S1 , respectively. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method (B3LYP) with the 6-311RRG(d,p) basis set. The vibrational frequencies were calculated and scaled values were compared with experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies are found to be in good agreement. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. 13 C and 1 H NMR chemical shifts results were compared with the experimental values. The optimized geometric parameters (bond lengths and bond angles) were given and are in agreement with the corresponding experimental values of aniline and p-methyl aniline.
Spectroscopic (FT-IR, FT-Raman and NMR) and computational studies on 3-methoxyaniline
Journal of Molecular Structure, 2014
h i g h l i g h t s Molecular structure of 3,5-difluorophenylboronic acid conformers and its dimer structure were investigated. Spectroscopic properties of 3,5-difluorophenylboronic acid were examined. The complete assignments were performed on the basis of the total energy distribution (TED). TDOS, PDOS and OPDOS were investigated.
Vibrational Spectral Investigations, NLO and Homo LUMO Analysis of 4-Chloro-2, 6-Dibromoaniline
Introduction Aniline and its derivatives have been widely used as starting materials in a vast amount of chemicals, pharmaceuticals, dyes, electro-optical and many other industrial processes [1-4]. The conducting polymer of aniline, namely, poly aniline is used in microelectronic devices as diodes and transistors [5-8]. Particularly, aniline and its derivatives are used in the production of dyes, pesticides and antioxidants. Consideration of these factors leads to undertake the detailed spectral investigation of 4-chloro-2, 6-dibromoaniline (CDBA). The aim of this work is to carry out an experimental and theoretical study on these compounds with the methods of quantum chemistry, in order to have a better understanding of its vibrational properties. However, for a proper understanding of IR and Raman spectra, reliable assignments of all vibrational bands are essential. Recently, computational methods based on density functional theory are being widely used. These methods predict a relatively accurate molecular structure and vibrational spectra with moderate computational effort. In particular, for polyatomic molecules, the DFT methods lead to the prediction of more accurate molecular structure and vibrational frequencies than the conventional ab initio restricted Hartree-Fock (HF) and Moller-Plesset second order perturbation theory (MP2) calculations [9-12]. To the best of our knowledge, there is no theoretical calculation to understand the structure and the fundamental vibrational frequencies of CDBA and PFA. This study is made to present a full description of the vibrational spectra of the title compounds, using ab initio HF and DFT (B3LYP) with 6-31+G(d,p) to obtain the geometries, vibrational frequencies, IR intensities and Raman activities. The atomic charges, distribution of electron density (ED) in various bonding and antibonding orbitals and stabilisation
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2010
Fourier-transform Raman and infrared spectra of 2-nitroanisole are recorded (4000-100 cm −1 ) and interpreted by comparison with respective theoretical spectra calculated using HF and DFT method. The geometrical parameters with C S symmetry, harmonic vibrational frequencies, infrared and Raman scattering intensities are determined using HF/6-311++G (d, p), B3LYP/6-311+G (d, p), B3LYP/6-311++G (d, p) and B3PW91/6-311++G (d, p) level of theories. A detailed vibrational spectral analysis has been carried out and assignments of the observed fundamental bands have been proposed on the basis of peak positions and relative intensities. The results of the calculations have been used to simulate IR and Raman spectra for the molecule that showed good agreement with the observed spectra. The SQM method, which implies multiple scaling of the DFT force fields has been shown superior to the uniform scaling approach. The vibrational frequencies and the infrared intensities of the C-H modes involved in back-donation and conjugation are also investigated.
2016
Extensive quantum chemical calculations of energy, geometrical structure, harmonic vibrational frequencies and the construction of theoretical spectrograms of IR and Raman spectra of the molecule, methyl 2,4-dihydroxy-6-methyl benzoate(methyl orsellinate) have been carried out by Hartree-Fock (HF) and Density Functional Theory (DFT/B3LYP) method with 6311++G(d, p) basis set. The assignments of normal modes of the vibration of the title molecule along with the observed frequencies (FT-IR and FTR) and scaled frequencies have been obtained by HF/DFT computation. The simulated NMR spectra are obtained by (GIAO) gauge independent atomic orbital method and their chemical shifts are compared with the experimental 13 C NMR and 1 H NMR spectra. Molecular geometric parameters, dipole moment, mullikan charge, thermodynamic properties, FMO analysis and NLO properties have also been computed and discussed in a detailed manner.The electrostatic potential surface and the mullikan charge analysis i...